1. Field of the Invention
The present invention relates to an apparatus and a method for reducing inter-cell interference in a wireless communication system. More particularly, the present invention relates to an apparatus and a method for addressing backhaul delay caused when a beamforming weight is generated in a multi-antenna system using a base station cooperative scheme.
2. Description of the Related Art
A multi-antenna system can adopt a base station cooperative scheme to reduce inter-cell interference. The multi-antenna system can mitigate the inter-cell interference using the base station cooperative scheme which is a multi-antenna scheme that extends various multi-antenna schemes used in a single cell to several base stations.
Using the base station cooperative scheme, the cooperating base stations should share channel information of terminals serviced with other base stations. For example, the base stations exchange the channel information with other base stations using a newly defined interface, such as an X2 interface.
When the cooperative base stations exchange the channel information as discussed above, processing delay and backhaul delay occur. For example, when the X2 interface is used as the backhaul between the base stations, the backhaul delay of 20 ms at maximum and 10 ms on average can occur as the base stations exchange the channel information.
As the base stations exchange the channel information, a channel between the base station and the terminal changes. Thus, the channel used for the base stations to determine the beamforming weight does not match the actual channel and the inter-cell interference rejection performance degrades.